2/19/2014. Indonesian Eruption Update for February 11, 2014: Kelut and Sinabung Erik Klemetti 2/11/2014

Transcription

1 Geology 15 Lecture 10 Schedule: HAZARD UPDATE! Earthquake Report Sign Up (1 at 50 points) First come first served Mid Term #1 3/3 200 points study guide next week 2/26 Review Lecture 8 Earth s Structure Bonus Activity Cover Material/Objectives Plate Boundary Faults Indonesian Eruption Update for February 11, 2014: Kelut and Sinabung Erik Klemetti 2/11/2014 Photo credit: tangga@gunung kelud kelut placed highest alert/ The dome within the crater at Kulet in Indonesia. This dome formed during the 2007 eruption of the volcano seen here in 2010 Over 200,000 people live within the 10 km evacuation zone near Indonesia s Kelud volcano, seen here topped by volcanic lightning, according to several media sources. Photo taken February 13, 2014 from Malang, East Java, Indonesia by EarthSky Photo on G+ community member Asthadi Setyawan. volcano East Java Indonesia eruption update ash plume drifting hundreds of km into the Indian.html volcano in indonesia is erupting thousands evacuating Kelut's eruption plume on MTSAT (infrared channel) (CIMSS)

2 Ashley Streig, Ph.D. Candidate, University of Oregon, Dept. of Geological Sciences (DOGS) Time space diagram for the SAS showing the distribution of paleoseismic investigation sites. Photomosaic log of cut D in T , overlain with linework; bold subvertical shaded lines are faults, and black and all other subhorizontal lines are unit horizons.

3 Earthquake Report Sign Up (1 at 50 points) First come first served Earthquake Report Sign Up (1 at 50 points) My Earthquake Report:

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6 How Seismology! do we know about the structure of the earth s interior? Differences in physical properties and strength. Differences in mineral and chemical composition. Refraction (Snell s Law) Can you think of a refraction example? Refraction Example

7 Why are there different layers? Why is some crust above sea level? Oceanic Crust Mean = 7 km Continental Crust Mean = 40 km ~2.7 g/cc ~3.3 g/cc ~4.5 g/cc Isostasy is the vertical movement of the crust to attain buoyancy in the mantle. The height a block of wood floats in water depends on it s density and thickness. The height of the earth s crust also depends on it s density and thickness.

8 Crustal Age Bathymetry Thermal Control on Crustal Depth Average depth ocean ridges = 2.5 km As plates cool, they get more dense and sink Depth = 2.5 km x (sq root age in Ma) Types of Plate Boundaries Spreading Centers Divergent (More Vectors!) Convergent Mid Atlantic Ridge = ~3.5 cm/yr East Pacific Rise = ~16.5 cm/yr Transform

9 East Pacific Rise = ~16.5 cm/yr Mid-Atlantic Ridge = ~3.5 cm/yr Transform Margins Connect spreading ridges Strike slip Transform Margins Connect spreading ridges Strike slip tails.aspx?guid=f6a2bf15 d163 4f3f a383 0f647bf374a4

10 Transform Boundaries Transform Margins Strike slip Loma Prieta 1989 Ms mm/yr NORTH AMERICA Davidson et al., 2002 PACIFIC San Andreas Fault, Carrizo Plain Convergent Margins a) Ocean Continent Subduction b) Ocean Ocean Subduction c) Continent Continent Collision Ocean Continent Subduction Anyone have an example?

11 Ocean Ocean Subduction Anyone have an example? Continent Continent Collision Anyone have an example? Convergent Margins Ocean Continent Subduction Ocean plate is subducted Continental arcs generated Explosive andesitic volcanic eruptions Cascadia subduction zone Juan de Fuca and Gorda plates subduct northeastwardly beneath the North America plate Subduction zone earthquakes can cause tsunami Ocean Continent Subduction Cascadia subduction zone Cross Section Water content fluxes melt to generate volcanism USGS

12 Ocean Continent Subduction Subduction zone earthquakes can generate tsunami Mt St Helens, WA March 1980 USGS Mt St Helens, WA May 18,1980 Types of Faults Strike Slip (e.g. transform faults) Strike slip faults Dip Slip (e.g. subduction zone faults) Thrust/Reverse faults Normal faults Association with Plate Boundaries

13 Handout Activity 3 Fault Types Fill this out as we review fault types in class today. This is due on Wednesday Pure Strike Slip Pure Normal Pure Thrust/Reverse Blind Thrust/Reverse Oblique Normal Oblique Reverse

14 Dip Slip Strike Slip Dip Slip Fig. 3 6, p. 36

15 LiDAR Topography 2/19/2014

16 muenchen.de/archiv/taiwan_/index.html ars.els cdn.com/content/image/1 s2.0 S X gr1.gif

17 ars.els cdn.com/content/image/1 s2.0 S gr1.gif Photograph of faulted sedimentary rock layers exposed on the beach in Santa Barbara. <<< The world famous Dr. John Caskey is standing in front of the world famous Tom Sawyer (both are HSU Geology graduates) Photo credit: J. R. Patton 2004

18 Photograph of faulted sedimentary rock layers exposed in a road cut in Guatemala. Which is the hanging wall and which is the footwall?

19 Wasatch fault Hilton Fault, McGee Creek, Ca Photo credit: J. R. Patton M6.6 EDGECUMBE, NZ, NORMAL

20 1954 M 7.3 DIXIE VALLEY, SS-NORMAL 1954 M 7.3 STILLWATER, SS-NORMAL What Plate Boundaries might these faults be associated with? Transform Divergent Convergent 1971, M 6.6 SAN FERNANDO, SS-REVERSE Convergent Divergent Convergent

21 Review Lecture 10 Plate Boundaries Types of Faults Associations of Faults with Plate Boundaries